JP4031114B2 - Boiler combustion control system - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a combustion control device for a boiler.
[0002]
[Prior art]
The start and stop of the boiler is controlled by the pressure value of the steam generated in the boiler.When the steam pressure value becomes lower than the combustion start pressure, which is the lower limit value, by using steam, combustion is started and steam is generated. When the combustion stop pressure becomes higher than the upper limit value, the steam pressure is controlled to be kept constant by stopping the combustion. At the start of combustion of the boiler, pre-purge is performed to ventilate the furnace by first operating the blower and sending air into the furnace. When pre-purge for a predetermined time is completed, the burner is burned with an ignition air volume that is lower than the pre-purge air volume. Is ignited and combustion is started.
[0003]
[Problems to be solved by the invention]
The boiler needs to be pre-purged before the start of combustion. Even if output of combustion start is performed due to pressure drop, combustion cannot be started immediately, and steam supply is delayed by that amount, so steam is insufficient There was a thing. The problem to be solved by the present invention is to provide a combustion control device in which steam is not insufficient due to a delay in starting combustion.
[0004]
[Means for Solving the Problems]
Steam detected by the pressure detection device having a pressure detection device for detecting the pressure of the steam generated in the boiler, a blower for introducing air into the furnace of the boiler, and an air amount adjusting means for adjusting the amount of air to be introduced. The pressure value is input to the control device, and when the steam pressure value is less than the combustion start pressure, combustion is performed, and when the steam pressure value is equal to or higher than the combustion stop pressure, the steam pressure value is even before the start of combustion pressure and the elapsed time from the stop of the operation of the boiler is detected that a predetermined value, by performing output to start the operation of the blower, and necessary combustion When the pre-purge for the pre-purge set time is completed, the pre-purge is performed in advance. Advance to prepare output for changing the ignition air volume smaller than the pre-purge air volume from the air volume, it performs output immediately ignited the steam pressure value becomes the start of combustion pressure and performs control to start the combustion of the boiler.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of a boiler in which a large number of four boilers are installed. Each boiler 3 takes out a burner (not shown) for generating a flame into the furnace, a blower 2 for sending air into the furnace, a damper device 5 for adjusting the air volume from the blower, and steam generated by the boiler. An operation control device 7 for controlling the steam take-out pipe 8 and each part of the boiler is provided.
[0006]
Each steam extraction pipe 8 is connected to a common steam header 6, and the steam header 6 is provided with a pressure detection device 1, and the number control device 4 connected to the pressure detection device 1 determines the number of boilers to be burned. . The number control device 4 determines the combustion amount of the boiler corresponding to the steam pressure value detected by the pressure detection device 1, and causes the boilers of the required number to be burned from the one with the highest combustion priority. Yes, the number control device 4 outputs a combustion execution signal and a combustion stop signal to the operation control device 7 of each boiler 3 so that the determined number of combustion is obtained.
[0007]
In addition, the number control device 4 receives a combustion start signal from one of the boilers with the highest combustion priority among the boilers with the combustion priority up to the third highest. The number control device 4 outputs the execution of the preceding pre-purge to the operation control device 7 of the corresponding boiler.
[0008]
FIG. 2 shows the operating state of each boiler. Combustion priority order is No. 1 can, No. 2 can, No. 3 can, No. 4 can. Initially, No. 1 can be burned, No. 2 can be pre-purge, No. 3 can and No. 4 can be stopped A signal is input from the number control device 4.
[0009]
The operation control device 7 receives a signal from the number control device 4 and controls the operation of each part of the boiler. The first can in the first combustion control order has received a combustion execution signal, and the first can is burning. The No. 2 can, which has the second highest combustion priority, has received a pre-purge signal, and the operation control device 7 having received the pre-purge signal operates the blower 2 and sets the damper position to the position of the pre-purge air flow to the damper device 5. By ventilating the furnace with a pre-purge air flow.
[0010]
The operation control device 7 that has started the preceding pre-purge also counts the pre-purge execution time, and performs the pre-purge by continuing the air blowing for a predetermined pre-purge setting time. When the count of the pre-purge execution time reaches the pre-purge setting time, the operation control device 7 outputs to the damper device 5 to change the damper position to the ignition air amount position, and by narrowing the damper opening, It is made to stand by in the state made into the amount of ignition air which is a low air volume.
[0011]
The 3rd and 4th cans of combustion priority 3rd and 4th received the stop signal, and the 3rd and 4th cans are stopped. Since the number of boilers that perform the pre-purge is set to one, the pre-purge is output only to the No. 2 can at this time, and the operation stop signal is output to the No. 3 can instead of the pre-purge. The
[0012]
When the steam pressure value detected by the pressure detection device 1 of the steam header 6 is lowered to a pressure at which combustion of the boiler with the second highest combustion priority is started, the unit control device 4 sends a signal for performing combustion to the operation of the No. 2 can. Output to the control device 7. The No. 2 can that has received the combustion execution signal has already completed the pre-purge and is waiting in the state of the amount of ignition air, and therefore can be ignited immediately. The operation control device 7 starts combustion of the burner and generates steam within a short time to prevent the steam from being insufficient, and the generated steam is sent to the steam header 6 through the steam extraction pipe 8.
[0013]
The number control device 4 outputs the start of combustion for the No. 2 can and outputs the pre-purge for the No. 3 can, and the No. 3 can performs the pre-purge as described above. When the steam pressure value detected by the pressure detection device 1 further decreases to a pressure at which combustion of the boiler with the third highest combustion priority is started, the unit control device 4 outputs the combustion execution to the No. 3 can. I do. If the combustion execution signal is input before the pre-purge set time has elapsed since the start of the pre-purge, the pre-purge is continued until the pre-purge set time has elapsed, and then the burner is ignited. Compared to the case where the preceding pre-purge is not performed, the supply of the steam can be started earlier by the amount of the preceding pre-purge which has been performed until the combustion execution signal is input, so that it is possible to prevent the steam from being insufficient.
[0014]
Thereafter, when the steam generation amount increases and the steam pressure in the steam header 6 increases and the number of combustion is reduced, the unit controller 4 stops the combustion with respect to the operation control unit 7 of the No. 3 can. Output is performed and the No. 3 can stops operation. Then, the number control device 4 detects the elapsed time from the operation stop of the No. 3 can, and when it detects that the elapsed time has passed the predetermined pre-purge waiting time, the pre-purge to the No. 3 can. Is output, and a pre-purge is performed in the No. 3 can.
[0015]
Since the pre-purge is set for the boiler with the combustion priority of up to the third place, the pre-purge is not performed for the No. 4 can with the combustion priority of the fourth place. Therefore, when the steam pressure is lowered to the combustion start pressure of the No. 4 can, pre-purge is started from that point, and combustion is started after the end of pre-purge. In this case, there is a possibility that the steam supply will be delayed, but it is usually possible to cover with 3 boilers, and since the 4th is rarely used, the advantage of preventing delay in steam supply However, when the demerit of the increase in energy consumption due to the operation of the blower is larger, the increase in energy consumption can be prevented by setting the pre-purge up to the third-ranked boiler.
[0016]
The output time of the pre-purge is determined after the steam pressure value detected by the pressure detection device 1 starts combustion, in addition to the case where the pre-purge waiting time elapses after the boiler described in the embodiment stops operating. The optimal standard is selected depending on the steam usage, such as when the pressure reaches a predetermined pressure higher than the pressure or when the boiler is stopped immediately after operation. In the boiler for performing the pre-purge, the boiler corresponding to the specific combustion priority is stopped when the execution of the pre-purge is output to one or a plurality of boilers from the boiler of the order of starting the next combustion. In some cases, the execution of the preceding pre-purge may be output, or they may be combined as in the embodiment, and the combustion is stopped in order to increase the number of boilers that perform the preceding pre-purge as the number of boilers performing the combustion decreases. The most appropriate one is selected according to the steam usage, such as performing a pre-purge for a certain percentage of the boiler.
[0017]
【The invention's effect】
By carrying out the present invention, when steam supply becomes necessary, combustion can be started immediately and supply of steam can be started, so that the shortage of steam can be prevented. Further, by preventing the preceding pre-purge from being performed more than necessary, it is possible to prevent heat loss due to the preceding pre-purge and excessive power consumption for operating the blower.
[Brief description of the drawings]
FIG. 1 is a block diagram of an embodiment of the present invention. FIG. 2 is an explanatory diagram showing the operation state of each boiler according to an embodiment of the present invention.
DESCRIPTION OF SYMBOLS 1 Pressure detection apparatus 2 Blower 3 Boiler 4 Number control apparatus 5 Damper apparatus 6 Steam header 7 Operation control apparatus 8 Steam extraction pipe

Claims (2)

Steam detected by the pressure detection device having a pressure detection device for detecting the pressure of the steam generated in the boiler, a blower for introducing air into the furnace of the boiler, and an air amount adjusting means for adjusting the amount of air to be introduced. The pressure value is input to the control device, and when the steam pressure value is less than the combustion start pressure, combustion is performed, and when the steam pressure value is equal to or higher than the combustion stop pressure, the steam pressure value is even before the start of combustion pressure and the elapsed time from the stop of the operation of the boiler is detected that a predetermined value, by performing output to start the operation of the blower, and necessary combustion When the pre-purge for the pre-purge set time is completed, the pre-purge is performed in advance. A boiler is characterized in that an output for changing the air volume from an air volume to an ignition air volume smaller than the pre-purge air volume is output, and when the steam pressure value reaches the combustion start pressure, the ignition is output immediately, and control is performed to start combustion of the boiler. Combustion control device.  In the boiler combustion control apparatus according to claim 1, in the case of multi-can installation in which a plurality of boilers are installed, it is possible to set a boiler that performs a pre-purge and a boiler that does not perform a pre-purge, and a pre-purge is performed only on a predetermined boiler. The boiler that is set to perform the preceding pre-purge outputs the preceding pre-purge that causes the pre-purge to be performed before the steam pressure value reaches the combustion starting pressure, and the other boilers have the combustion starting pressure and A boiler combustion control apparatus characterized by performing normal output for starting pre-purge after becoming.

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